D-rings are used in a wide variety of different applications and for many different purposes in the construction industry. One common use of D-rings is for use in association with safety harnesses and belts wherein one end of the D-ring is secured to a belt or strap worn around the body of a worker. The other end of the D-ring has an opening to receive a hook attached to a safety belt or strap that is secured around a fixed object in order to prevent or limit falls while working on elevated structures.
It will be appreciated that in many instances safety harnesses, including attached D-rings, must be of a dielectric nature so that they will not conduct electricity in the event that an individual comes into contact with live electrical wires. It will also be appreciated that to be able to withstand sufficient loading, traditionally D-rings have been made from steel or a high strength metallic compound. Previously metallic D-rings have been coated with dielectric material through crude methods of dipping the rings into liquid baths of plastic or rubberized material, or by spraying a liquid dielectric material over the D-ring and allowing it to dry. In either instance the result is somewhat unsatisfactory as the thickness of the dielectric coating either cannot (or with only great effort and expense) be accurately maintained. In addition, in both instances there will always be a "hang point" where no dielectric coating is initially applied that must later be filled in. For example, when applying coatings by means of dipping, the D-ring must be grasped or held along some portion of its surface and thereafter dipped into a vat containing the dielectric material. Similarly, in order to spray a coating on the D-ring, the ring must be held along some portion of its surface, effectively creating a "hang point" In both cases the area where the ring is held does not receive any coating and must be filled in later to ensure a complete dielectric covering over the entire surface of the ring.
Hang points that have been later filled with coating material result in increased manufacturing costs and also represent a weakness in the surface of the coating material and a potential point of failure. Furthermore, in most instances the application of a liquid coating material by way of dipping can result in "runs" in the material on the surface of the D-ring, that in turn can have the effect of producing an uneven exterior surface, or causing a thinning of the coating material along certain portions of the ring. In either case, the results are undesirable. Finally, in many cases where there is not a chemical bonding of the coating material to the material from which the D-ring blank is constructed the coating is only loosely held against the ring's surface. These loosely held coatings can shift or slide during use of the ring.